symfony compiler pass to detect invalid classes on service configurations

ValidateServiceDefinitions.php

<?php

declare(strict_types=1);

namespace Infrastructure\Symfony\DependencyInjection\Compiler;

use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\Definition;

/**
 * Look at *all* service definitions and validate that their classes exist.
 *
 * With autoconfigure but no autowire, we otherwise never see invalid class
 * names for listeners or such.
 *
 * This needs to be a compilar pass running at PassConfig::TYPE_BEFORE_REMOVING.
 * A command would only see the services that have not been removed from the
 * container.
 *
 * Inspired by https://github.com/matthiasnoback/symfony-service-definition-validator/ which is
 * very outdated and validates some things that Symfony will detect and report.
 */
class ValidateServiceDefinitions implements CompilerPassInterface
{
    private const KNOWN_UNUSED_SERVICES = [
        'beberlei_metrics.util.buzz.curl' => true, // not cleaned out by bundle
        'beberlei_metrics.util.buzz.browser' => true, // not cleaned out by bundle
        'form.type.entity' => true, // breaks when loading the php file
        'debug.file_link_formatter.url_format' => true, // configured to by "string"
        'service_container' => true, // ContainerInterface but no factory
    ];

    public function process(ContainerBuilder $container): void
    {
        foreach ($container->getDefinitions() as $serviceId => $definition) {
            if ($definition->isAbstract() || \array_key_exists($serviceId, self::KNOWN_UNUSED_SERVICES)) {
                continue;
            }
            $class = $definition->getClass();
            if ($class) {
                $class = $container->getParameterBag()->resolveValue($class);

                if (!class_exists($class)) {
                    if (null === $definition->getFactory() || !interface_exists($class)) {
                        throw new \Exception(sprintf('Service %s is configured to use the nonexistent class %s', $serviceId, $class));
                    }
                }
            } elseif (!$definition->isSynthetic()) {
                throw new \Exception(sprintf('Service %s has no class', $serviceId));
            }
        }
    }
}